Methods and systems for delivery of multiple passive optical network services

ABSTRACT

A system for delivering multiple passive optical network services is disclosed. The system includes a first optical transmission service comprising a common wavelength pair routed from a source to each of a plurality of subscribers. The system further includes a second optical transmission service comprising a plurality of unique wavelength pairs, where each of the unique wavelength pairs is routed from the source to a subscriber among the plurality of subscribers. The system delivers the first optical transmission service and the second optical transmission service to the subscriber on a single optical fiber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 14/054,153,filed Oct. 15, 2013, which is a continuation of application Ser. No.12/257,020, filed Oct. 23, 2008, now U.S. Pat. No. 8,559,818, whichapplication claims priority to provisional application Ser. No.61/000,753, filed Oct. 26, 2007, which applications are incorporatedherein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates generally to delivery of passive opticalnetwork services, such as from an optical service provider to a home orbusiness. More specifically, the present disclosure relates to methodsand systems for delivery of multiple passive optical network services.

BACKGROUND

Passive optical networks are becoming prevalent in part because serviceproviders want to deliver high bandwidth communication capabilities tocustomers. Passive optical networks are a desirable choice fordelivering high speed communication data because they may not employactive electronic devices, such as amplifiers and repeaters, between acentral office and a subscriber termination. The absence of activeelectronic devices may decrease network complexity and cost and mayincrease network reliability.

Passive optical networks may take a signal from a single incoming fiberand make it available to a number of output fibers. For example, adistribution cable may include 24 optical fibers and may run from acentral office to a distribution location, such as an equipmentenclosure. At the equipment enclosure, each fiber in the distributioncable may be split into a number of outgoing fibers which are madeavailable to subscribers. For example, passive optical networks mayemploy 1:2, 1:4, 1:8, 1:16 and 1:32 splitting ratios for each fiber, formaking optical data available to subscriber locations.

In traditional gigabit passive optical network a single transmitwavelength and a single receive wavelength are used in each 1:32 split,requiring 32 subscribers to share bandwidth on a single fiber. However,in other systems, such as DWDM systems, dedicated wavelengths are usedfor each subscriber. Conversion between gigabit and DWDM systemsrequires substantial reconfiguration of the optical network to takeadvantage of the dedicated wavelength system. In certain instances,replacing wires leading to subscriber locations would be required. Suchre-cabling is costly and time-consuming.

For these and other reasons, improvements are desirable.

SUMMARY

The above and other problems are solved in accordance with the presentdisclosure by the following:

In a first aspect, a system for delivering multiple passive opticalnetwork services is disclosed. The system includes a first opticaltransmission service comprising a common wavelength pair routed from asource to each of a plurality of subscribers. The system furtherincludes a second optical transmission service comprising a plurality ofunique wavelength pairs, where each of the unique wavelength pairs isrouted from the source to a subscriber among the plurality ofsubscribers. The system delivers the first optical transmission serviceand the second optical transmission service to the subscriber on asingle optical fiber.

In a second aspect, a method for delivering multiple passive opticalnetwork services is disclosed. The method includes splitting a firstoptical transmission service from source to a plurality of subscribers,the first optical transmission service including a common wavelengthpair. The method further includes separating a second opticaltransmission service including a plurality of unique wavelength pairsonto a corresponding plurality of optical fibers, where each opticalfiber receives a unique wavelength pair associated with a subscriberamong the plurality of subscribers. The method also includes routing thefirst and second wavelengths of the first optical transmission serviceand the first and second wavelengths of the second optical transmissionservice to the subscriber on a single optical fiber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a typical network in which aspects of the presentdisclosure can be implemented;

FIG. 2 shows a schematic view of a system for delivery of multiplepassive optical network services, according to one embodiment of thepresent disclosure;

FIG. 3 shows a schematic view of a system for delivery of multiplepassive optical network services, according to a second embodiment ofthe present disclosure; and

FIG. 4 shows a schematic view of a system for delivery of multiplepassive optical network services, according to a third embodiment of thepresent disclosure.

DETAILED DESCRIPTION

Various embodiments of the present invention will be described in detailwith reference to the drawings, wherein like reference numeralsrepresent like parts and assemblies throughout the several views.Reference to various embodiments does not limit the scope of theinvention, which is limited only by the scope of the claims attachedhereto. Additionally, any examples set forth in this specification arenot intended to be limiting and merely set forth some of the manypossible embodiments for the claimed invention.

In general, the present disclosure relates to delivery of multiplepassive optical network services to a single endpoint, such as ahousehold, a business, or other entity requiring a telecommunicationsconnection to a distribution hub. The present disclosure describes avariety of passive optical network configurations which allow forselective use of one or more of the passive optical network services,thereby allowing selective upgrading of endpoints based on customerdesires or requirements. The methods and systems of the presentdisclosure allow use of the same optical fibers already deployed tocustomer homes.

The present disclosure is designed to enable providers ofdata/video/voice services who have currently deployedfiber-to-the-premise (FTTP) distribution networks for those services, beable to upgrade customers to higher data rate & bandwidth service(s)while maintaining the other services in their current delivery format.For example, a service provider may upgrade its data service to deliverindividual customers with a 1 Gbps data line via a DWDM passive opticalnetwork (DWDM PON) while continuing to deliver voice and video to thatsame customer on its traditional gigabit PON (GPON). However, both wouldbe delivered to the customer premise on the same already installedfiber. In this example, the service provider would not have to upgradeall of its delivery equipment to work with the new DWDM PON system butcan use the fiber network that is already deployed in the field todeliver all of these services.

In various examples of the present disclosure, delivery of gigabitpassive optical networks and DWDM passive optical networks areconsidered; however, deployment of additional types of optical networksis possible as well using the systems and techniques disclosed herein.For example the present disclosure also relates to delivery of othertypes of systems with different wavelengths and parallelism, such asWDM-PON and CWDM-PON.

Referring now to FIG. 1, a generalized network in which aspects of themethods and systems of the present disclosure may be implemented. Thenetwork 10 as shown is a passive optical network (PON) such as cancontain various Fiber-to-the-premises (FTTP) systems. The network 10connects a source 102, such as a central office of a telecommunicationsprovider, to various subscribers 104, allowing the subscribers highspeed data communications to other subscribers within the network andoutside of the network (through other communication channels of thesource). The network 10 includes a number of fiber optic components 103that allow the network to route specific fiber optic signals to a subsetof the entire subscriber base, thereby allowing the central office 102to manage bandwidth concerns. The components can include, for example,splices, splitters, wavelength division multiplexers, repeaters,filters, and other optical components. These components may be modularlyadded or removed from the fiber optic system, such as by placing variouscombinations of such equipment in a fiber distribution hub or othermodularly extensible system. The systems of the present disclosurebreakout multifiber cable down to single fiber, limited wavelengthspectra to allow a small number of users to share a particular availablebandwidth. For example, in the case of gigabit PON, 32 subscribers 104typically share a single wavelength for transmitting and receiving datawith the source 102. In the case of DWDM PON, each subscriber has adedicated wavelength pair which it uses to communicate with the source102, thereby effectively increasing the bandwidth to that subscriber ascompared to gigabit PON by eliminating competing traffic using thatsubscriber's communication wavelength.

Referring now to FIGS. 2-4, various systems for delivery of multiplepassive optical network services are shown. These systems can be locatedwithin the network 10 of FIG. 1, and provide at least a portion of theconnecting optical components used to connect a source 102 tosubscribers 104.

Referring now to FIG. 2, a schematic view of a system 100 for deliveryof multiple passive optical network services is shown, according to oneembodiment of the present disclosure. The system 100 connects opticalfibers from a source 102, shown as a central office or OLT, to one ormore subscribers 104, shown as customers or ONT connections. The systemreceives an initial distribution fiber 106 leading from the source 102,on which all spectra of optical transmission coexist.

In the embodiment shown, the spectra of optical transmission include (1)a common wavelength pair and (2) a plurality of unique wavelength pairs.According to certain implementations the common wavelength pair is a1310 nm wavelength and a 1490 nm wavelength used in gigabit passiveoptical network systems. In such systems, the 1490 nm wavelength is usedto transmit data from the source 102 to all of the subscribers 104,while the 1310 nm wavelength is used by all of the subscribers totransmit data back to the source. Other common wavelengths may be usedas well with different types of optical services.

The unique wavelength pairs include a predetermined number of wavelengthpairs, each of which connects to a single subscriber. By dedicating awavelength pair to each subscriber, that subscriber will not need toshare the bandwidth available for that wavelength pair with othersubscribers on a passive optical network, thereby allowing for higherdata rates due to parallel transmission of the different uniquewavelength pairs. Selection of the various unique wavelength pairs islargely a matter of design choice; however, in a possible embodiment,the wavelength pairs are the corresponding C-Band and E-Band frequenciesused in DWDM data transmission.

A wavelength division multiplexer 108 is connected to the fiber 106, andseparates the common wavelength signals from the unique wavelengthsignals. In the embodiment shown, the common wavelength gigabit PONsignals (1310 and 1490 nm signals) are split to a fiber 110, while theDWDM PON signals are split to fiber 112.

The unique wavelength signals (e.g. DWDM PON signals) on fiber 112 arepassed through a 1×N wavelength division multiplexer 114, whichseparates the signals onto N different fibers. In the embodiment shown,there are N different DWDM PON signals on fiber 112, and each of thesesignals is broken out onto a separate fiber 116 _(1-N).

The gigabit PON signals on fiber 110 are passed to a splitter 120, whichsplits the signals into a corresponding number of optical fibers 122_(1-N), each carrying the common wavelength pair signals. In theembodiment shown, the splitter 120 is a 1×N splitter, corresponding tothe 1×N wavelength division multiplexer 114. Each of optical fibers 116_(1-N) and 122 _(1-N) are passed into separate wavelength divisionmultiplexers 124 _(1-N), (of which only WDM 124 ₁ and 124 _(N) areshown, for simplicity) which combine the common wavelength pair signalson the optical fibers 122 _(1-N) with each individual (and nowseparated) unique wavelength pair signal on optical fibers 116 _(1-N) toform subscriber lines 126 _(1-N), which carry both the common wavelengthpair signals and one of the sets of unique wavelength pair signals to asubscriber 104 (e.g. 104 ₁and analogously to other subscribers 104_(2-N)).

Through use of the system 100, a subscriber 104 therefore receives thecommon wavelength signals and one of the pairs of unique wavelengthsignals, allowing two different passive optical network services (e.g.gigabit PON and DWDM PON) to be delivered to the subscriber withoutrequiring rewiring or additional wiring to the subscriber's premises.

Referring now to FIG. 3, a schematic view of a system 200 for deliveryof multiple passive optical network services is shown, according to asecond embodiment of the present disclosure. The system 200 generallycorresponds to system 100 of FIG. 2 in effect, but separates andrecombines the common wavelength pair and unique wavelength pairs in aslightly different manner. Specifically, the optical fiber 106 leadingfrom the source 102 connects to a 1×2 splitter 208, which splits, butdoes not filter, the common wavelength pairs and the unique wavelengthpairs onto optical fibers 110 and 112. One path connects to a 1×N DWDM214, which filters out the common wavelength signal and also splits theunique wavelength signals onto N corresponding fibers 116 _(1-N), aspreviously described. The second path includes a filter 209 connected tothe fiber 110, which filters out the unique wavelength pairs, leavingonly the common wavelength signal on a fiber 211 leading from thefilter. The fiber 211 leads to a 1×N splitter 120 as previouslydescribed, which outputs the common wavelength signals onto fibers 122_(1-N). The common wavelength signal, carried on each of fibers 122_(1-N), is combined with each individual unique wavelength signal on thefibers 116 _(1-N) via 1x2 splitters 224 _(1-N). The splitters 224 _(1-N)are connected to output cables 126 _(1-N), which connect to subscribers104 _(1-N).

Referring now to FIG. 4, a schematic view of a system 300 for deliveryof multiple passive optical network services is shown, according to athird embodiment of the present disclosure. In this embodiment, thesystem 300 includes an AWG DWDM 350 connecting optical fiber 106 fromthe source 102 to the various subscribers 104 _(1-N). The AWG DWDMseparates the unique wavelength signals, while allowing the commonwavelength signals to pass to all of the output fibers 126 _(1-N) thatlead to various customers 104 _(1-N).

Alternative designs exist in which multiple fibers are used leading fromthe source 104. For example, in the systems of FIGS. 2 and 3, above,separate fibers could be used leading from the source 104 carrying theunique wavelength pairs to the wavelength division multiplexer 114, 214and the common wavelength pairs to the splitter 120 of FIGS. 2 and 3,respectively. This would eliminate the need for the wavelength divisionmultiplexer 108 of FIG. 2 or the splitter 208 and filter 209 of FIG. 3.Other embodiments are possible as well which include different levelsand combinations of splitters, filters, and wavelength divisionmultiplexers.

In the embodiments shown in FIGS. 2-4, the systems for delivery ofmultiple passive optical network services are illustrated as passiveoptical modules. However, it is understood that the system can beconfigured from a number of separate components, and could includeadditional passive or active optical components. Furthermore, additionaloptical networking components can be incorporated into networks havingthe systems described herein.

Through use of the systems disclosed herein, a provider of passiveoptical network services can connect multiple services to a singlesubscriber location while avoiding the need to lay additional fibers tothose locations. A provider or maintainer of an optical network such asare disclosed herein can install the splitters, filters, and wavelengthdivision multiplexers as described herein to split a common wavelengthpair into a number of fibers, and to separate unique wavelength pairsonto a corresponding number of fibers. The fibers carrying the commonwavelength pair can be joined to each one of the fibers carryingdifferent unique wavelength pairs to allow connection of a subscriber toeither one or both services by using a single preexisting optical fiberconnected to the subscriber.

The above specification, examples and data provide a completedescription of the manufacture and use of the composition of theinvention. Since many embodiments of the invention can be made withoutdeparting from the spirit and scope of the invention, the inventionresides in the claims hereinafter appended.

1-11. (canceled)
 12. A system for delivering multiple passive opticalnetwork services comprising: a first optical transmission servicecomprising a common wavelength pair routed from a source to each of aplurality of subscribers; a second optical transmission servicecomprising a plurality of unique wavelength pairs, each of the uniquewavelength pairs routed from the source to a subscriber among theplurality of subscribers; a splitter configured to receive the firstoptical transmission service from the source on a single optical fiberand distribute the first optical transmission service onto a pluralityof separate optical fibers; a passive optical component joining one ofthe plurality of separate optical fibers with a fiber carrying one ofthe plurality of unique wavelength pairs of the second opticaltransmission service to provide the first optical transmission serviceand the second optical transmission service on a single subscriber-sideoptical fiber.
 13. The system of claim 12, wherein the passive opticalcomponent comprises an optical splitter.
 14. The system of claim 13,further comprising a plurality of passive optical components includingthe passive optical component, the plurality of passive opticalcomponents each joining a respective one of the plurality of separateoptical fibers with one of a second plurality of fibers carrying adifferent one of the plurality of unique wavelength pairs of the secondoptical transmission service.
 15. The system of claim 14, wherein eachof the plurality of passive optical components outputs the first opticaltransmission service and the second optical transmission service on aseparate single subscriber-side optical fiber.
 16. The system of claim15, further comprising a wavelength division multiplexer configured toreceive the second optical transmission service from the source on asingle optical fiber, the wavelength division multiplexer configured toseparate each of the unique wavelength pairs of the second opticaltransmission service onto the second plurality of optical fibers. 17.The system of claim 12, wherein the source is a central office of afiber optic communications service provider.
 18. The system of claim 17,wherein the first and second optical transmission services connect tothe source on a single optical fiber.
 19. The system of claim 12,wherein, in the first optical transmission service, the first wavelengthis 1490 nm and the second wavelength is 1310 nm.
 20. The system of claim12, wherein the plurality of unique wavelength pairs of the secondoptical transmission service correspond to C-Band and E-Band frequenciesuseable in DWDM data transmission.
 21. The system of claim 12, whereinthe splitter and passive optical component are located at a distributionlocation.
 22. The system of claim 12, wherein the splitter comprises a1×N passive optical splitter.